This invention relates generally to temperature sensors and controllers and more specifically to an electronic temperature sensor and controller that is adapted to replace conventional mechanical wall thermostats widely employed in connection with residential and commercial heating and cooling systems.
Temperature sensing and control functions have been traditionally accomplished using mechanical thermostats. These devices are inherently not very accurate, are basically unuseable in hostile weather environments, are not capable of performing multiple remote temperature sensing, and do not interface easily to the wide variety of sophisticated electronic computers on the market today.
While attempts have been made over the past several years to sense and control temperature electronically, those attempts have been somewhat limited in application due to high cost resulting from the use of relatively complex circuitry, the time consuming and difficult procedures involved in calibrating to a reasonably high degree of accuracy, and the inability to perform long range remote temperature sensing without suffering a degradation in accuracy.
Accordingly, the principal objects of the present invention are to provide an electronic temperature sensor/controller system that is more economical and reliable due to its efficient, simplified circuitry, that achieves higher accuracy while eliminating the need for multiple point calibration of each sensor, and that is capable of performing long range remote temperature sensing while maintaining that high degree of accuracy.
These objects are accomplished in accordance with the illustrated preferred embodiment of the invention by employing one or more sensing devices, a precision voltage reference, a pair of analog multiplexers, a voltage-to-frequency converter, a microcomputer, a keyboard, an output display, and one or more solid state switches.